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Pierre-Olivier Combelles

Coral fossil of the High Andes of Peru

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Pierre-Olivier Combelles    2
Pierre-Olivier Combelles

Hi!

In the same (calcareous) region of Lake Junin (or Lake Chinchaycocha, in quechua), in the High Central Andes of Peru, where I was investigating Maca (Lepidium meyenii Walpers) I found in tne 1990's this nice coral fossil specimen at the altitude of 4200/4300m. Measure below in cm. What do you think about it ?

 

Thank you in advance !

 

Warmfully

 

 

Pierre-Olivier Combelles

Institut Andin d'Etudes Ehnobiologiques (France)

 

 

Corail fossile Junin Peru Photo PO Combelles.JPG

Mapa Andes 1855 detalle.jpg

Edited by Pierre-Olivier Combelles

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Guguita    138
Guguita

Hi!

It looks like a branching coral.

Do you know the age of the layers?

 

Regards,

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Pierre-Olivier Combelles    2
Pierre-Olivier Combelles

No, I don't know. I found it on the ground (the puna). This region is calcareous.

Edited by Pierre-Olivier Combelles
Precision

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Pierre-Olivier Combelles    2
Pierre-Olivier Combelles

Measure below the coral in cm.

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FossilDAWG    1,835
FossilDAWG

Hi Pierre-Olivier,

 

Your coral is a nice specimen, but unfortunately corals cannot be identified just from a side view.  You need to see the internal structure, showing both cross and longitudinal sections.  Can you photograph any parts of the specimen that would show any detail like that?  Close-up views of the top and the bottom would also perhaps be helpful.

 

For a really confident identification, thin sections would have be cut and mounted on slides.  It is possible that your specimen has been replaced by silica, that is suggested by the way it has weathered out of the encasing limestone.  Unfortunately silicification often obscures the original detailed structure, though there is no way to know for your specimen based on the one photo.  There are thousands of described species of coral, which is why so much detail is needed for a confident identification.

 

Don

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Pierre-Olivier Combelles    2
Pierre-Olivier Combelles
On 23/02/2017 at 11:51 PM, FossilDAWG said:

Hi Pierre-Olivier,

 

Your coral is a nice specimen, but unfortunately corals cannot be identified just from a side view.  You need to see the internal structure, showing both cross and longitudinal sections.  Can you photograph any parts of the specimen that would show any detail like that?  Close-up views of the top and the bottom would also perhaps be helpful.

 

For a really confident identification, thin sections would have be cut and mounted on slides.  It is possible that your specimen has been replaced by silica, that is suggested by the way it has weathered out of the encasing limestone.  Unfortunately silicification often obscures the original detailed structure, though there is no way to know for your specimen based on the one photo.  There are thousands of described species of coral, which is why so much detail is needed for a confident identification.

 

Don

Thank you very much Don, for your kind explainations ! This specimen is in my collections in Peru and I am actually in France. But when I shall be back in S. AM., I shall do it with some paleobiologist friends. So, keeping in touch, all the best !

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Pierre-Olivier Combelles    2
Pierre-Olivier Combelles

An interesting paper from french IRD (Institut de Recherche pour le Développement) of 2005:

 

The Lower Carboniferous of the western edge of Gondwana in Peru and
Bolivia: Distribution of sedimentary basins and associated magmatism
Alberto Zapata M. \ Agapito Sanchez F. '. Segundo Carrasco V. 1, Agustin Cardona 2, Jorge
Galdos H. 1, Fredy Cerrôn Z. 1, & Thierry Sempere 3

1 Direction of Regional Geology, Instituto Geologico Minero Metalurgico (INGEMMET), Lima, Peru
2 Phd student of the University of Sâo Paulo, Brazil
3 IRD, LMTG, Observatoire Midi-Pyrénées, 14 avenue Edouard Belin, 31400 Toulouse, France

 

6th International Symposium on Andean Geodynamics (ISAG 2005, Barcelona), Extended Abstracts: 817-820

 

http://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers09-03/010040372.pdf

 

Would date the fossils of this area and our coral, in the Carboniferous,  somewhere between Tournaisien (-358.9) and Serpoukhovien (-323.2). See the extract below ("Junin-Huancavelica Sector"): Ambo Group.

 

As said in the abstract of the paper, we are here in the western edge of Gondwana:

 

"During the Early Carboniferous, the tectono-sedimentary and rnagrnatic configuration of the western edge of Gondwana (Eastern Cordillera of Peru and Cordillera Real of Bolivia, between latitudes 3°S and 24°S; Figure 1) associated a marine and continental sedimentation (Ambo Group), a volcanic arc (Lavasen Formation) and a related plutonism (Pataz-Balsas-Buldibuyo batholith, Higueras pluton , Amparaes and Cadenas granites). "

Carbonifère Wikipedia.jpg

Junin paléogenèse IRD.jpg

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